October 29, 1997
12:00 AM (EST)

News Release Number: STScI-1997-35

Hubble Catches Up with a Blue Straggler Star

October 29, 1997: Astronomers have long been mystified by observations of a few hot, bright, apparently young stars residing in well-established communities where most of their neighbors are much older.

With the help of the Hubble telescope, astronomers now have evidence that may eventually help solve the 45-year-old mystery of how these enigmatic stars, called blue stragglers, were formed. For the first time, astronomers have confirmed that a blue straggler in the core of a globular cluster (a very dense community of stars) is a massive, rapidly rotating star that is spinning 75 times faster than the Sun. This finding provides proof that blue stragglers are created by collisions or other intimate encounters in an overcrowded cluster core. A ground-based telescope image [left] shows the crowded core of the globular cluster 47 Tucanae, which is teeming with blue stragglers. Peering into the heart of the cluster's brilliant core, Hubble separated the dense clump of stars into many individual stars [right].